-# Copyright (c) 2016 Cisco and/or its affiliates.
+# Copyright (c) 2018 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
# TODO: load priv key
+class SSHTimeout(Exception):
+ """This exception is raised when a timeout occurs."""
+ pass
+
+
class SSH(object):
"""Contains methods for managing and using SSH connections."""
:param node: Node in topology.
:type node: dict
- :return: IP address and port for the specified node.
+ :returns: IP address and port for the specified node.
:rtype: int
"""
return hash(frozenset([node['host'], node['port']]))
- def connect(self, node):
+ def connect(self, node, attempts=5):
"""Connect to node prior to running exec_command or scp.
If there already is a connection to the node, this method reuses it.
"""
- self._node = node
- node_hash = self._node_hash(node)
- if node_hash in SSH.__existing_connections:
- self._ssh = SSH.__existing_connections[node_hash]
- logger.debug('reusing ssh: {0}'.format(self._ssh))
- else:
- start = time()
- pkey = None
- if 'priv_key' in node:
- pkey = RSAKey.from_private_key(
- StringIO.StringIO(node['priv_key']))
-
- self._ssh = paramiko.SSHClient()
- self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
-
- self._ssh.connect(node['host'], username=node['username'],
- password=node.get('password'), pkey=pkey,
- port=node['port'])
-
- self._ssh.get_transport().set_keepalive(10)
-
- SSH.__existing_connections[node_hash] = self._ssh
-
- logger.trace('connect took {} seconds'.format(time() - start))
- logger.debug('new ssh: {0}'.format(self._ssh))
-
- logger.debug('Connect peer: {0}'.
- format(self._ssh.get_transport().getpeername()))
- logger.debug('Connections: {0}'.format(str(SSH.__existing_connections)))
+ try:
+ self._node = node
+ node_hash = self._node_hash(node)
+ if node_hash in SSH.__existing_connections:
+ self._ssh = SSH.__existing_connections[node_hash]
+ logger.debug('reusing ssh: {0}'.format(self._ssh))
+ else:
+ start = time()
+ pkey = None
+ if 'priv_key' in node:
+ pkey = RSAKey.from_private_key(
+ StringIO.StringIO(node['priv_key']))
+
+ self._ssh = paramiko.SSHClient()
+ self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
+
+ self._ssh.connect(node['host'], username=node['username'],
+ password=node.get('password'), pkey=pkey,
+ port=node['port'])
+
+ self._ssh.get_transport().set_keepalive(10)
+
+ SSH.__existing_connections[node_hash] = self._ssh
+
+ logger.trace('connect took {} seconds'.format(time() - start))
+ logger.debug('new ssh: {0}'.format(self._ssh))
+
+ logger.debug('Connect peer: {0}'.
+ format(self._ssh.get_transport().getpeername()))
+ logger.debug('Connections: {0}'.
+ format(str(SSH.__existing_connections)))
+ except RuntimeError as exc:
+ if attempts > 0:
+ self._reconnect(attempts-1)
+ else:
+ raise exc
def disconnect(self, node):
"""Close SSH connection to the node.
ssh = SSH.__existing_connections.pop(node_hash)
ssh.close()
- def _reconnect(self):
+ def _reconnect(self, attempts=0):
"""Close the SSH connection and open it again."""
node = self._node
self.disconnect(node)
- self.connect(node)
+ self.connect(node, attempts)
logger.debug('Reconnecting peer done: {}'.
format(self._ssh.get_transport().getpeername()))
:type timeout: int
:return return_code, stdout, stderr
:rtype: tuple(int, str, str)
- :raise socket.timeout: If command is not finished in timeout time.
+ :raise SSHTimeout: If command is not finished in timeout time.
"""
- start = time()
stdout = StringIO.StringIO()
stderr = StringIO.StringIO()
try:
chan = self._ssh.get_transport().open_session(timeout=5)
+ peer = self._ssh.get_transport().getpeername()
except AttributeError:
self._reconnect()
chan = self._ssh.get_transport().open_session(timeout=5)
+ peer = self._ssh.get_transport().getpeername()
except SSHException:
self._reconnect()
chan = self._ssh.get_transport().open_session(timeout=5)
+ peer = self._ssh.get_transport().getpeername()
chan.settimeout(timeout)
- logger.trace('exec_command on {0}: {1}'
- .format(self._ssh.get_transport().getpeername(), cmd))
+ logger.trace('exec_command on {peer} with timeout {timeout}: {cmd}'
+ .format(peer=peer, timeout=timeout, cmd=cmd))
+
+ start = time()
chan.exec_command(cmd)
while not chan.exit_status_ready() and timeout is not None:
if chan.recv_ready():
stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
if time() - start > timeout:
- raise socket.timeout(
- 'Timeout exception.\n'
- 'Current contents of stdout buffer: {0}\n'
- 'Current contents of stderr buffer: {1}\n'
- .format(stdout.getvalue(), stderr.getvalue())
+ raise SSHTimeout(
+ 'Timeout exception during execution of command: {cmd}\n'
+ 'Current contents of stdout buffer: {stdout}\n'
+ 'Current contents of stderr buffer: {stderr}\n'
+ .format(cmd=cmd, stdout=stdout.getvalue(),
+ stderr=stderr.getvalue())
)
sleep(0.1)
stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
end = time()
- logger.trace('exec_command on {0} took {1} seconds'.format(
- self._ssh.get_transport().getpeername(), end-start))
-
- logger.trace('chan_recv/_stderr took {} seconds'.format(time()-end))
+ logger.trace('exec_command on {peer} took {total} seconds'.
+ format(peer=peer, total=end-start))
- logger.trace('return RC {}'.format(return_code))
- logger.trace('return STDOUT {}'.format(stdout.getvalue()))
- logger.trace('return STDERR {}'.format(stderr.getvalue()))
+ logger.trace('return RC {rc}'.format(rc=return_code))
+ logger.trace('return STDOUT {stdout}'.format(stdout=stdout.getvalue()))
+ logger.trace('return STDERR {stderr}'.format(stderr=stderr.getvalue()))
return return_code, stdout.getvalue(), stderr.getvalue()
def exec_command_sudo(self, cmd, cmd_input=None, timeout=30):
:param cmd: Command to be executed.
:param cmd_input: Input redirected to the command.
:param timeout: Timeout.
- :return: return_code, stdout, stderr
+ :returns: return_code, stdout, stderr
:Example:
command = 'sudo -S {c} <<< "{i}"'.format(c=cmd, i=cmd_input)
return self.exec_command(command, timeout)
+ def exec_command_lxc(self, lxc_cmd, lxc_name, lxc_params='', sudo=True,
+ timeout=30):
+ """Execute command in LXC on a new SSH channel on the connected Node.
+
+ :param lxc_cmd: Command to be executed.
+ :param lxc_name: LXC name.
+ :param lxc_params: Additional parameters for LXC attach.
+ :param sudo: Run in privileged LXC mode. Default: privileged
+ :param timeout: Timeout.
+ :type lxc_cmd: str
+ :type lxc_name: str
+ :type lxc_params: str
+ :type sudo: bool
+ :type timeout: int
+ :returns: return_code, stdout, stderr
+ """
+ command = "lxc-attach {p} --name {n} -- /bin/sh -c '{c}'"\
+ .format(p=lxc_params, n=lxc_name, c=lxc_cmd)
+
+ if sudo:
+ command = 'sudo -S {c}'.format(c=command)
+ return self.exec_command(command, timeout)
+
def interactive_terminal_open(self, time_out=30):
"""Open interactive terminal on a new channel on the connected Node.
- :param time_out: Timeout in seconds.
- :return: SSH channel with opened terminal.
+ FIXME: Convert or document other possible exceptions, such as
+ socket.error or SSHException.
.. warning:: Interruptingcow is used here, and it uses
signal(SIGALRM) to let the operating system interrupt program
handlers only apply to the main thread, so you cannot use this
from other threads. You must not use this in a program that
uses SIGALRM itself (this includes certain profilers)
+
+ :param time_out: Timeout in seconds.
+ :returns: SSH channel with opened terminal.
+ :raise IOError: If receive attempt results in socket.timeout.
"""
chan = self._ssh.get_transport().open_session()
chan.get_pty()
chan.set_combine_stderr(True)
buf = ''
- while not buf.endswith(':~$ '):
+ while not buf.endswith((":~$ ", "~]$ ", "~]# ")):
try:
chunk = chan.recv(self.__MAX_RECV_BUF)
if not chunk:
logger.error('Channel exit status ready')
break
except socket.timeout:
- raise Exception('Socket timeout: {0}'.format(buf))
+ logger.error('Socket timeout: {0}'.format(buf))
+ # TODO: Find out which exception would callers appreciate here.
+ raise IOError('Socket timeout: {0}'.format(buf))
return chan
def interactive_terminal_exec_command(self, chan, cmd, prompt):
interactive_terminal_open() method has to be called first!
- :param chan: SSH channel with opened terminal.
- :param cmd: Command to be executed.
- :param prompt: Command prompt, sequence of characters used to
- indicate readiness to accept commands.
- :return: Command output.
-
.. warning:: Interruptingcow is used here, and it uses
signal(SIGALRM) to let the operating system interrupt program
execution. This has the following limitations: Python signal
handlers only apply to the main thread, so you cannot use this
from other threads. You must not use this in a program that
uses SIGALRM itself (this includes certain profilers)
+
+ :param chan: SSH channel with opened terminal.
+ :param cmd: Command to be executed.
+ :param prompt: Command prompt, sequence of characters used to
+ indicate readiness to accept commands.
+ :returns: Command output.
+ :raise IOError: If receive attempt results in socket.timeout.
"""
chan.sendall('{c}\n'.format(c=cmd))
buf = ''
logger.error('Channel exit status ready')
break
except socket.timeout:
- raise Exception('Socket timeout: {0}'.format(buf))
+ logger.error('Socket timeout during execution of command: '
+ '{0}\nBuffer content:\n{1}'.format(cmd, buf))
+ # TODO: Find out which exception would callers appreciate here.
+ raise IOError('Socket timeout during execution of command: '
+ '{0}\nBuffer content:\n{1}'.format(cmd, buf))
tmp = buf.replace(cmd.replace('\n', ''), '')
- return tmp.replace(prompt, '')
+ for item in prompt:
+ tmp.replace(item, '')
+ return tmp
@staticmethod
def interactive_terminal_close(chan):
"""
chan.close()
- def scp(self, local_path, remote_path):
- """Copy files from local_path to remote_path.
+ def scp(self, local_path, remote_path, get=False, timeout=10):
+ """Copy files from local_path to remote_path or vice versa.
connect() method has to be called first!
+
+ :param local_path: Path to local file that should be uploaded; or
+ path where to save remote file.
+ :param remote_path: Remote path where to place uploaded file; or
+ path to remote file which should be downloaded.
+ :param get: scp operation to perform. Default is put.
+ :param timeout: Timeout value in seconds.
+ :type local_path: str
+ :type remote_path: str
+ :type get: bool
+ :type timeout: int
"""
- logger.trace('SCP {0} to {1}:{2}'.format(
- local_path, self._ssh.get_transport().getpeername(), remote_path))
+ if not get:
+ logger.trace('SCP {0} to {1}:{2}'.format(
+ local_path, self._ssh.get_transport().getpeername(),
+ remote_path))
+ else:
+ logger.trace('SCP {0}:{1} to {2}'.format(
+ self._ssh.get_transport().getpeername(), remote_path,
+ local_path))
# SCPCLient takes a paramiko transport as its only argument
- scp = SCPClient(self._ssh.get_transport())
+ scp = SCPClient(self._ssh.get_transport(), socket_timeout=timeout)
start = time()
- scp.put(local_path, remote_path)
+ if not get:
+ scp.put(local_path, remote_path)
+ else:
+ scp.get(remote_path, local_path)
scp.close()
end = time()
logger.trace('SCP took {0} seconds'.format(end-start))
def exec_cmd(node, cmd, timeout=600, sudo=False):
"""Convenience function to ssh/exec/return rc, out & err.
+ FIXME: Document :param, :type, :raise and similar.
Returns (rc, stdout, stderr).
"""
if node is None:
Code Review / csit.git / blobdiff